Plastic self-venting gagger for sand molds



Sept. 26, 1967 KEssLER PLASTIC SELF-VENTING GAGGER FOR SAND MOLDS Filed June 28, 1965 FIG.

INVENTOR Milton Kessler ATTORNEY United States Patent 3,343,595 PLASTIC SELF-VENTING GAGGER FOR SAND MOLDS Milton Kessler, 4535 Grove Drive,

Youngstown, Ohio 44505 Filed June 28, 1965, Ser. No. 467,256 4 Claims. (Cl. 164-349) ABSTRACT OF THE DISCLOSURE A plastic gagger is provided to replace the metal gaggers now commonly used in sand molds to reinforce the sand, hold cores in place, prevent displacement of the parts of a mold, etc. The gagger is in the form of a bent rod, usually Z-shaped. Since the high casting temperature may volatilize the plastic gagger to some extent, a small axial bore is provided through the gagger, which bore serves as a gas receptacle to prevent entrained gas from ruining the casting.

Gaggers are commonly used for the above purposes in sand molds, and have heretofore been made of metal, usually steel, bent into various shapes to serve the desired purpose. However, such gaggers have a number of known disadvantages; they are expensive and therefore are generally reclaimed for re-use, by sifting the sand out of them in a rotary sieve. Due to the strength and hardness of the metal gaggers, they occasionally puncture the rotary sieve, and in any event tend to cause excessive wear thereof. After being sifted, they are usually placed on a conveyor for return to the starting point in the plant, and again, because of their hardness and rigidity, occasionally jamb or cut the conveyor. Furthermore, metal gaggers occasionally become displaced during the pouring of the molten metal into the mold, so that a part of the gagger enters the mold cavity, and becomes embedded in the final casting, which generally ruins the casting. This difiiculty is termed springers and together with the othermentioned difliculties, is obviated by the present invention.

According to the present invention, the gaggers, similar in shape to those made of metal, are made of plastic, suitably rigid vinyl plastic, which is inexpensive, does not injure sieves or eonveyers, and serves the intended function in the sand mold at least as well as steel. A common type of gagger, which is employed in a typical plant at the rate of 10,000-20,000 units a Week, is made of coiled round steel stock, bent into a suitable shape, usually in the form of a modified Z, Simply replacing this shape with plastic material, however, does not entirely solve the problem, because the plastic material is, of course, incapable of withstanding as high tempeartures as steel, and therefore those gaggers, or portions of gaggers which are near the surface of the casting, at the high temperatures involved, tend to volatilize and produce a gas which may cause defects in either the sand mold or the casting due to the entrained gas at high pressure, which may also spoil the casting.

In accordance with the present invention, this problem is solved by providing the gagger, which is typically of round stock, wtih a central axis aperture extending throughout its length, and which serves as a receptacle for any gases which may be formed, so that they do not produce the above-mentioned damage. It will be understood that the sand used in molds for casting metals is treated with various binders, and is more or less impermeable to the gases formed, so that they cannot readily escape through the sand.

The specific nature of the invention, as well as other objects and advantages thereof, will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing, in which:

FIG. 1 is a sectional view through a typical sand mold, showing various ways in which gaggers may be used to strengthen and rigidify the mold;

FIG. 2 is a side view of a typical gagger according to the invention, partly broken away, to show the axial aperture; and

FIG. 3 is a sectional view taken on line 3-3 of FIG. 2.

As shown in FIG. 1, the gaggers 2 may be used in either the cope or the drag, or to hold the two parts of the mold together. In practice, they are liberally distributed through the sand 3 of the mold wherever experience indicates that such reinforcing is necessary. The customary shape is as shown, with a long central shank 4, typically about fifteen inches long, a short leg 6, about two inches long, and a longer leg 7, about five inches long. Such gaggers, made of steel, are used by the thousands in sand casting of metals. The present gagger is made of suitable plastic, preferably polyvinyl chloride (PVC), of a formulation sufficiently rigid for the purpose. This material has the still further advantage of being capable of being bent by hand into a desired shape, wherever a spacial shape or configuration of the gagger is required.

As shown in FIGS. 2 and 3, the gagger is provided with a small axial aperture extending throughout its length. It has been found that, for the case of a gagger having a diameter of about 0.337 inch, the central aperture 8 may be approximately 0.04 inch and still perform its desired function. Other things being equal, it is desirable to keep the central aperture as small as possible, the walls of the tube thus formed being very much thicker than the diameter of the aperture, whereby the tube functions essentially as a rod, and can be readily bent to the desired shape without substantial distortion at the corner where the bend occurs. In the case of relatively thin-walled tubing, not only would the strength he insufiicient for the desired purpose, but at the bending corner 9, the walls would tend to collapse, thus weakening the gagger, which must have substantial strength in order to serve its purpose. Aperture 8 provides a pocket for any gases which may be formed.

While the gagger has been shown as circular in crosssection, it will be apparent that it may also be square or any other desired shape in cross section, but in any case should be provided with an aperture sufiiciently large to retain any gases formed upon overheating of a portion of the gagger, while being sufliciently small not to appreciably affect the strength or bending qualities of the unit.

The plastic gagger can be made very inexpensively, since it can be extruded of scrap material of any color, as the external appearance and color are of no importance for the present application.

While the dimensions given are typical for use in connection with many large castings, it will be understood that these can vary considerably, depending upon the size and type of casting, and upon the physical requirements for a particular casting.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of the invention as defined in the appended claims.

I claim:

1. In combination, a sand mold and a plurality of gaggers embedded in the sand thereof, each said gagger being made of plastic material which volatilizes at or near the temperature of molten casting metals, each said gagger being in the form of an elongated rod-like member of uniform cross-section along its length, said member having angular bent sections along its length for engaging and retaining the formed molding sand in the sand mold, said 3 rod-like member being axially apertured throughout its length, including the bent sections, so as to form a thick- Walled tube, the wall of which is of greater thickness than the maximum diametric extent of the aperture, whereby the angular sections can be formed by simple bending Without appreciably distorting the cross-section of the gagger at the bend.

2. The invention according to claim 1, said plastic material being polyvinylchloride plastic formulated to be cold-bendable.

3. The invention according to claim 1, said gagger being generally Z-shaped with the legs of the Z at right angles to the shank.

4. The invention according to claim 3, said gagger being circular in cross-section, with the axial aperture located at the center.

4 References Cited STATES PATENTS UNITED 12/1910 Rinebolt 22l 11 2/1921 Bradley 22-111 6/1921 McIlvried 138177 X 8/1936 Stassi 239-33 X 6/1951 Butsch 23933 7/1953 Jones 23933 10/1965 Roach et a1. 138-177 X FOREIGN PATENTS 1962 France, v

J. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner. 

1. IN COMBINATION, A SAND MOLD AND A PLURALITY OF GAGGERS EMBEDDED IN THE SAND THEREOF, EACH SAID GAGGER BEING MADE OF PLASTIC MATERIAL WHICH VOLATILIZES AT OR NEAR THE TEMPERATURE OF MOLTEN CASTING METALS, EACH SAID GAGGER BEING IN THE FORM OF AN ALONGATED ROD-LIKE MEMBER OF UNIFORM CROSS-SECTION ALONG ITS LENGTH, SAID MEMBER HAVING ANGULAR BENT SECTIONS ALONG ITS LENGTH FOR ENGAGING AND RETAINING THE FORMED MOLDING SAND IN THE SAND MOLD, SAID ROD-LIKE MEMBER BEING AXIALLY APERTURED THROUGHOUT ITS LENGTH, INCLUDING THE BENT SECTIONS, SO AS TO FORM A THICKWALLED TUBE, THE WALL OF WHICH IS OF GREATER THICKNESS THAN THE MAXIMUM DIAMETRIC EXTENT OF THE APERTURE, WHEREBY THE ANGULAR SECTIONS CAN BE FORMED BY SIMPLE BENDING WITHOUT APPRECIABLY DISTORTING THE CROSS-SECTION OF THE GAGGER AT THE BEND. 